Report post migration from Financial Reports - how to evaluate difference 2 text values in Reports?

Summary:

We have started the migration process from Financial Reports to Reports for PBCS Planning. One issue we have discovered post migration is a common formula that was used for determining the difference of 2 columns that have non-number values (text) is not returning the same results. An example is Formula = Difference(col[A],col[B])

We have some suppression settings and conditional formatting that come into play as well, but it seems the resulting value of the formula is different. Has anyone else ran into something similar? Is there a different function other than "Difference" that should be used when evaluating text rather than number values in Reports?